So there I had the idea of creating snow with lots of different flakes. Put 2 dozens of them into an AnimBrush and saved that, then used this as souce in Particle FX. BUT: while in brush mode I have the animation option "random and hold", this isn't present in the FX menu. I tried what was there, but none gave me what I wanted: randomly choose a frame of the brush and hold it for the life of that particle. (I also saved the brush with "random and hold" which doesn't make any difference.)

There are actually many options missing in particles (it's the only effect that won't let you access classical options like clip, layers, project, etc...), so I am not surprised that animation modes are also missing.

OK, I exported every single snowflake separately, then put them into particles via duplicating/renaming particle, click shape, browse ... and this 26times. I really hate to work like this with a computer, this is the sort of job it is supposed to be good at!

I've noticed some more things: the little profile popup needs to be closed by click, it lacks an OK button (and to be closed with return). This is a general UI topic: I think wherever possible, things need to be navigatable/closeable via keyboard, for power users or when you have to repeatedly adjust stuff.

That is a very nice stylized 3D effect. Reminds me of those flat geometric designs which reveal 3D form when you slightly relax your focus..........in the way it surprises me how much depth it seems to have.